For the determination of the stability of coastlines, coastal erosion and the design of erosion protection studies, the “local” wave climate is the most important input parameter. For morphology, “local” means just outside the breaker line. On relatively calm days the local wave climate is strongly influenced by the effect of sea breeze. On the basis of the sea breeze model of HAURWITZ [1947] and HSU [1988] an operational method has been developed for the determination of sea breeze and the effect on coastal morphology. Examples are presented from Cartagena, Colombia, and from the Bulgarian Black Sea coastline.